At tea, Raina was not out on 132 and giving him company was Ishwar Pandey on 29.
Rohit added another 49 runs to his overnight score, and put on a solid 106-run stand with Raina for the fourth wicket before he got dismissed for 119, studded with 14 boundaries and two sixes.
It was J P Duminy who got the breakthrough on the day when he had Rohit caught at the short leg by Temba Bavuma.
Joined by Ajinkya Rahane (10) in the middle, Raina continued to play his strokes, even as the the former got out cheaply when Duminy added another wicket to his kitty.
Duminy struck once again to get rid of Wriddhiman Shah (1) as India were reduced to 418 for six from 376 for four.
But that did not deter Raina from scoring at brisk pace. He brought up his ton in the 141st over.
And despite Duminy’s successive strikes, Raina in the able company of Ishwar Pandey continued to torment home bowlers. The duo has already put on an unbeaten 71-run partnership for the seventh wicket with Pandey hitting two fours and an equal number of sixes during his 29 not out, while Raina struck 14 fours and three sixes.